Distribution and characterization of ampicillin- and tetracycline-resistant Escherichia coli from feedlot cattle fed subtherapeutic antimicrobials
2011

Study of Antibiotic Resistance in Cattle

Sample size: 531 publication 10 minutes Evidence: moderate

Author Information

Author(s): Mirzaagha Parasto, Louie Marie, Sharma Ranjana, Yanke L Jay, Topp Ed, McAllister Tim A

Primary Institution: Agriculture and Agri-Food Canada, Lethbridge Research Centre

Hypothesis

Feeding subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR E. coli from cattle.

Conclusion

Factors other than, or in addition to subtherapeutic administration of antibiotics influence the establishment and transmission of AMR E. coli among feedlot cattle.

Supporting Evidence

  • Resistance to amikacin, ceftriaxone, cefoxitin, or nalidixic acid was not detected in any of the isolates.
  • Subtherapeutic administration of antibiotics had only a limited impact on the nature of antimicrobial resistance in E. coli.
  • Most isolates exhibited multi-drug resistance.
  • Factors such as diet and animal age may influence the prevalence of AMR E. coli.

Takeaway

This study looked at how feeding cattle antibiotics affects the germs in their guts. It found that even without antibiotics, some germs can still be resistant to medicine.

Methodology

E. coli isolates were recovered from cattle and characterized using susceptibility testing and pulsed field gel electrophoresis.

Potential Biases

The study may not have captured the full genetic diversity of resistant E. coli due to selective isolation methods.

Limitations

Resource constraints limited the characterization to single isolates from each selective plate.

Participant Demographics

Cattle were housed in groups of 10 in a feedlot setting.

Statistical Information

P-Value

p<0.05

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1186/1471-2180-11-78

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